Time-interleaved multistage heat pipe-assisted adsorptive dehumidification for stable and high-efficiency supply air control

This study proposes a multistage heat pipe-assisted adsorptive dehumidifier (HP-AD) designed to address the inherent limitations of conventional desiccant systems, such as excessive supply air temperature rise and high regeneration energy requirements. A fundamental deficiency in single-module HP-ADs is the occurrence of high-amplitude, sawtooth wave-like fluctuations in the supply air’s hydrothermal states. These instabilities are intrinsically tied to the adsorption/desorption kinetics of the adsorbent coupled with the discrete 180° rotation cycles of the module, which collectively compromise the consistency of indoor air quality. To mitigate these fluctuations, a multistage architecture comprising five adsorbent-coated fin-heat pipe modules was developed and experimentally validated. Central to this system is a time-interleaved operational sequence, where each module rotates 180° based on a predefined phase-shift interval to achieve quasi-steady-state dehumidification. To maximize thermal effectiveness via the thermosyphon effect, the heat pipes were oriented parallel to the gravitational vector, enabling the latent heat of the working fluid to passively recover adsorption heat and facilitate water vapor desorption in the regeneration section. Experimental results demonstrate that the five-stage configuration significantly stabilizes the outlet conditions, achieving a 59.5% reduction in temperature variation and a 91.5% decrease in humidity fluctuation compared to a single-module baseline. Furthermore, the moisture removal rate and coefficient of performance improved by 2.9 and 2.5 times, respectively, due to superior thermal utilization. These findings validate the proposed system as a high-performance, high-efficiency, and robust prototype for advanced ventilation applications requiring high-precision indoor air quality control.